1. Abelson H Anderson RN Bellovin SM. . The Risks of Key Recovery, Key Escrow, and Trusted Third-Party Encryption, 1997. http://academiccommons.columbia.edu/catalog/ac:127127 (26 October 2015, date last accessed).
2. Advanced Telephony Unit, Federal Bureau of Investigation. Telecommunications Overview, Slide on Encryption Equipment, 1992. https://www.cs.columbia.edu/∼smb/Telecommunications_Overview_1992.pdf (26 October 2015, date last accessed).
3. Nakashima E. Chinese hackers who breached Google gained access to sensitive data, U.S. officials say. The Washington Post, May 2013. https://www.washingtonpost.com/world/national-security/chinese-hackers-who-breached-google-gained-access-to-sensitive-data-us-officials-say/2013/05/20/51330428-be34-11e2-89c9-3be8095fe767\_story.html (26 October 2015, date last accessed).
4. Dam KW Lin HS. . Cryptography’s Role in Securing the Information Society. National Academies Press, 1996.
5. Comey JB . Going Dark: Are Technology, Privacy, and Public Safety on a Collision Course? Speech at the Brookings Institution, October 2014. https://www.fbi.gov/news/speeches/going-dark-are-technology-privacy-and-public-safety-on-a-collision-course (26 October 2015, date last accessed).